The present invention relates to a disc drive microactuator system, and more particularly to a side shield layer for protecting a transducing head from fringe fields generated by the microactuator.
The density of concentric data tracks on magnetic discs continues to increase (that is, the radial spacing between data tracks is decreasing), requiring more precise radial positioning of the head. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuation motor, such as a voice coil motor, to radially position a head on a flexure at the end of the actuator arm. The large-scale motor lacks sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism, or microactuator, is necessary to accommodate the more densely spaced tracks. Various microactuator locations and designs have been considered to achieve high resolution head positioning. One promising design involves inserting a silicon-based thin-film structure between the suspension and the slider in the disc drive assembly. The microactuator includes, for example, an electromagnetic transducer having magnetic core materials having a stator and a rotor, with conductive coils wrapped around the stator core in a solenoid-type or planar-type configuration. One example of a high performance electromagnetic microactuator is disclosed in the aforementioned U.S. application Ser. No. 09/010,100, now U.S. Pat. No. 6,122,149, which is hereby incorporated by reference.
It is important when implementing an electromagnetic microactuator to ensure that fringe fields from the microactuator do not degrade the performance of the transducing head carried by the disc drive slider over the rotating disc media. Magnetoresistive (MR) heads are sensitive to magnetic fields, and giant magnetoresistive (GMR) heads even more so. Magnetic fields generated by the electromagnetic microactuator can potentially have significant effects on the off-track capability (OTC) performance of MR and GMR heads. The present invention is directed to microactuator systems, such as that described in the Zhang et al. U.S. Pat. No. 6,122,149 to prevent degradation of transducing head performance.